Pursuing an acting career, Any Advice?

I am 15 years old, male, sopre in high school. I am very interested in becoming an actor, and making a career in this area. Any advice on where i can get started as far as getting a gig, or an audition for a commercial or something? I'd love to be viewed as the next Adam Sandler, or Bruce Willis, just having a big name! I know it's a big dream, but any advice on where i can start with small time stuff would help. Thanks(: